Thank you very much for your answer.
In my opinion it makes no sense to have offset- or normalmapping on default ID1 Quake models/textures.
There are no offset-files for them in orig. Quake.
So you would only "fake" an existing offset texture.
The visuals will be not good
Only if external offset files (_norm or _bump) are available, then they should be used, when enabling "r_glsl_offsetmapping" "1"
This is exactly the way it was until 3rd february 2011 build
After this date things changed. In my opinion to a not good way.
"Faking" normal textures for a diffuse (external or original ID1) texture will always result in a not good visual (see screen in my post #41 above).
Look how long it takes to create a external normal texture by hand.
An automated software emulation will never reach its visual.
I know there are other engines, that "try" to do just this.
But the visual is always not good in my opinion.
So going back to the way things was handled till 3rd february is my favorite:
If you dont have any external offset textures and enable "r_glsl_offsetmapping" "1"
you should not see any difference to "r_glsl_offsetmapping" "0"
Maybe I am completely wrong with my opinion.
But working on visual enhancements for DarkPlaces for a very long time now,
makes me believe that this is the best solution.
Thank you for your time reading this.